This week, I focused on the system integration of my final project The Honor Tree, which is an interactive classroom display that celebrates students’ achievements.
The Honor Tree consists of multiple components working together:
| Component | Quantity | Unit Price (RMB) | Notes |
|---|---|---|---|
| PLA Filament | 93g | -- | Provided by FabLab Formshop |
| 3mm Corrugated Cardboard | 3 pcs | -- | Laser-cut tree structure |
| 9mm Felt Board | 1 | 21.8 | Tree background |
| Seeed XIAO-ESP32-C3 | 1 | 34.05 | Main microcontroller |
| WS2812B RGB LEDs | 8 pcs | 17.36 | Light up apples |
| A3144 Hall Sensor | 8 pcs | 17.6 | Detect magnetic apples |
| Neodymium Magnets | 8 pcs | 3.3 | Inside 3D-printed apples |
| DFPlayer Mini | 1 | 39 | Plays sound effects |
| Speaker (3W 8Ω) | 1 | 4.12 | Connected to DFPlayer |
| SD Card (8GB) | 1 | 3.7 | Stores MP3 files |
I designed a custom PCB using EasyEDA based on the XIAO ESP32-C3,A total of 8 pins are required for the Hall sensors and 1 for the LED, plus two pins for the mini player, along with power and ground pins. No additional pin expansion board is needed for the Xiao.
PCB board
D0–D5 & D8-D10 are connected to Hall sensors and WS2812B LEDs.D6 and D7 are connected to DFPlayer Mini.
Overall circuit layout diagram
A 3D-printed apple contains an embedded magnet. When the magnet approaches the Hall sensor, the corresponding WS2812B LED lights up.
Cutouts for the LED lights, Hall sensor, and the 3D-printed apple support.
When a student attaches their apple:
This provides immediate feedback and motivates students through interactive celebration.
Here is my first version — an Honor Tree made of a wooden box. Since the surface area was relatively small, I upgraded to the second version to enhance the visual effect.
Integrating all the parts was challenging yet rewarding. Aligning structure and electronics required multiple iterations. The result is a beautiful and meaningful classroom interaction tool that helps students feel recognized and proud of their efforts.